This invention relates to the dyeing of textile fibers, and in particular to a continuous process for dyeing textile fabrics formed at least partially of cationic dyeable polyester fibers.
Cationic dyeable polyester has become increasingly popular in recent years as a textile fiber, primarily because cationic dyes are capable of producing brighter shades than regular (disperse) dyeable polyester. In practice, the cationic dyeable polyester is frequently combined with other fibers, such as regular (disperse) dyeable polyester, wool, or cellulosic fibers, to produce various multicolor or cross-dyed effects. It is also known to use cationic dyeable polyester in combination with other fibers which are unaffected by cationic dyes to thereby achieve color/white effects.
Insofar as applicants are aware, the dyeing of cationic dyeable polyester fibers has been restricted to batch methods, normally at intermediate temperatures of up to about 105 to 115 degrees C. High temperature processes, such as the Thermosol process, are not suitable for cationic dyeable polyester because the high temperatures destroy the dye sites. Moreover, because the relative dyeing speed of cationic dyeable polyester is considerably lower than that of other conventional fibers, it has been thought important to allow time for diffusion of the dyes into the fibers after they have been exhausted from the dyebath, and this is best accomplished only in batch dyeing methods.
It is therefore an object of the present invention to provide a method for continuously dyeing cationic dyeable polyester fibers or blends of cationic dyeable polyester with other fibers such as regular dyeable polyester.
In commonly-assigned U.S. Pat. application Ser. No. 653,941 filed Sept. 20, 1984 entitled METHOD FOR DYEING POLYESTER FABRICS, a process is disclosed in which fabrics containing regular (disperse) dyeable polyester fibers can be continuously dyed. This process involves impregnating the fabrics with an aqueous dyebath containing
(a) 0 to 5.0 g/l of a thickener;
(b) commercially available disperse dyestuffs in an amount sufficient to dye the fibers to the desired depth of color;
(c) 2 to 100 g/l of a partially sulfated adduct of ethylene oxide with alkylphenol or C.sub.8 to C.sub.16 fatty alcohols;
(d) 0 to 60 g/l of nonionic or anionic surfactants; and
(e) 5 to 50 g/l of at least one organic compound selected from the group consisting of aromatic nitrile ethers and ethoxylated chlorophenols.
Although cationic dyeable polyester fibers behave quite differently from disperse dyeable polyester fibers, and are normally dyed by processes which are fundamentally different from the processes used for disperse dyeable polyester, it has been discovered in accordance with the present invention that a dyebath composition similar to that noted above can be successfully employed for continuously dyeing cationic dyeable polyester fibers, which, as earlier noted, have not heretofore been dyed in a continuous process.